Problem: Luis ate 4 slices of pizza. Christopher ate 3 slices. If Luis ate $\dfrac{4}{11}$ of the pizza, what fraction of the pizza is remaining?
Answer: If 4 slices represent $\dfrac{4}{11}$ of the pizza, there must have been a total of 11 slices. $\text{fraction of pizza remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 7 slices, which leaves 4 out of 11 slices remaining. There is $\dfrac{4}{11}$ of the pizza remaining.